Inclination measurement in process transmitters

Abstract

A process control system includes a process sensor, an inclination sensor and transmitter circuitry. The process sensor senses the process variable of a process fluid and the inclination sensor senses the orientation of the transmitter. The transmitter circuitry produces an output based on the sensed process variable and the sensed orientation.

1. A process transmitter for measuring a process variable, the process transmitter comprising:
 a process sensor for sensing the process variable of a process; 
 an inclination sensor for sensing a stationary orientation of the process transmitter; 
 transmitter circuitry for producing an output based on the sensed process variable and the sensed stationary orientation; and 
 an LCD screen having a display output based on the output of the circuitry, and wherein the circuitry adjusts an orientation of the display output based on the stationary orientation of the transmitter sensed by the inclination sensor. 
 
     
     
       2. The process transmitter of  claim 1  wherein the inclination sensor comprises a tri-axis accelerometer for generating a three-dimensional acceleration vector. 
     
     
       3. The process transmitter of  claim 2  wherein the transmitter circuitry determines a stationary inclination of the transmitter with respect to a reference three-dimensional coordinate system based on an output of the inclination sensor. 
     
     
       4. The process transmitter of  claim 3  wherein the transmitter circuity determines a local three-dimensional rotational displacement of the transmitter from the stationary inclination based on the three-dimensional acceleration vector generated by the inclination sensor with respect to the three-dimensional coordinate system. 
     
     
       5. The process transmitter of  claim 3  wherein the transmitter circuitry records transmitter orientation data. 
     
     
       6. The process transmitter of  claim 3  wherein the transmitter circuitry is pre-programmed with a starting, three-dimensional reference position from which the stationary inclination is determined with reference to the three-dimensional coordinate system. 
     
     
       7. The process transmitter of  claim 4  wherein the transmitter circuitry determines mechanical vibration of the transmitter based on changes in the sensed stationary orientation of the transmitter and the three-dimensional acceleration vector. 
     
     
       8. The process transmitter of  claim 1  wherein the transmitter circuitry annunciates information relating to output of the inclination sensor. 
     
     
       9. The process transmitter of  claim 1  and further comprising a hydraulic fill fluid for conveying the process variable to the process sensor, wherein the fill fluid produces a head effect on the process sensor based on the stationary orientation of the process transmitter wherein the transmitter circuitry calibrates the output to account for a change in head effect resulting from a change in the stationary orientation of the transmitter, wherein the calibration utilizes the stationary orientation of the transmitter sensed by the inclination sensor. 
     
     
       10. The process transmitter of  claim 9  wherein the transmitter circuitry adjusts the calibration for fill fluids having varying properties. 
     
     
       11. The process transmitter of  claim 9  wherein the transmitter circuitry calibrates the output based on software algorithms. 
     
     
       12. The process transmitter of  claim 1  wherein the output comprises a process variable signal generated by the process sensor compensated with a stationary orientation signal from the inclination sensor. 
     
     
       13. The process transmitter of  claim 12  wherein the compensated process variable signal is calibrated with respect to gravity. 
     
     
       14. A method for adjusting an output of a process transmitter, the method comprising:
 sensing a process variable of a process with a process sensor to produce a sensor signal; 
 sensing a stationary orientation of the process transmitter with an inclination sensor to produce an orientation signal; 
 conveying the process variable to the process sensor with hydraulic fill fluid, wherein the fill fluid produces a head effect on the process sensor based on the stationary orientation of the process transmitter wherein the transmitter circuitry calibrates the output to account for a change in head effect resulting from a change in the stationary orientation of the transmitter, wherein the calibration utilizes the stationary orientation of the transmitter sensed by the inclination sensor; and 
 producing an adjusted transmitter output with transmitter electronics, the transmitter output being based on the sensor signal and the orientation signal. 
 
     
     
       15. The method of  claim 14  wherein the adjusted transmitter output comprises a local display output. 
     
     
       16. The method of  claim 14  wherein the adjusted transmitter output comprises a process variable magnitude. 
     
     
       17. The method of  claim 16  wherein the step of producing an adjusted transmitter output comprises calibrating the sensor signal due to a change in head effect on the process sensor based on a change in orientation of the transmitter. 
     
     
       18. The method of  claim 16  wherein the step of producing an adjusted transmitter output further comprises adjusting the adjusted transmitter output for fill fluid properties. 
     
     
       19. The method of  claim 17  wherein producing an adjusted transmitter output is further based on software algorithms. 
     
     
       20. A process transmitter for measuring a process variable, the process transmitter comprising:
 a process sensor for sensing the process variable of a process; 
 an inclination sensor for sensing an orientation of the process transmitter; 
 a hydraulic fill fluid for conveying the process variable to the process sensor, wherein the fill fluid produces a head effect on the process sensor based on the orientation of the process transmitter; 
 transmitter circuitry for producing an output based on the sensed process variable and the sensed orientation, wherein the transmitter circuitry calibrates the output to account for a change in head effect resulting from a change in the orientation of the transmitter, wherein the calibration utilizes the orientation of the transmitter sensed by the inclination sensor. 
 
     
     
       21. The process transmitter of  claim 20  wherein the circuitry adjusts its output based on an original orientation of the transmitter as compared with a current orientation of the transmitter determined by the inclination sensor. 
     
     
       22. The process transmitter of  claim 20  and further comprising an LCD screen having a display based on output of the circuitry, and wherein the circuitry adjusts the display based on the orientation signal. 
     
     
       23. The process transmitter of  claim 20  wherein the inclination sensor is a tri-axis accelerometer. 
     
     
       24. The process transmitter of  claim 20  wherein the transmitter circuitry records the sensed orientation of the transmitter. 
     
     
       25. The process transmitter of  claim 20  wherein the transmitter circuitry annunciates that calibration of the head effect has changed. 
     
     
       26. The process transmitter of  claim 20  wherein the transmitter circuitry determines an inclination of the transmitter based on output of the inclination sensor. 
     
     
       27. The process transmitter of  claim 26  wherein the transmitter circuitry determines a local displacement of the transmitter based on the inclination signal. 
     
     
       28. The process transmitter of  claim 20  wherein the transmitter circuitry is adjustable for fill fluids having varying properties. 
     
     
       29. The process transmitter of  claim 20  wherein the transmitter circuitry performs vibration filtering based on the inclination signal.